The present invention relates to a direction indicator and hazard warning device for motor vehicles.
A device of this type is shown in German Published Unexamined Patent Application No. 3,147,682. This known equipment permits the drivers of vehicles, which have to be driven with the hazard warning signal switched on during a towing procedure or after a breakdown, to superimpose on the hazard warning signal present on all sides, direction indicator signals, for turning off or changing lanes, by switching on the direction indicator switch. This is providing that the driving switch or the ignition switch of the vehicle concerned is switched on. This switching capability is achieved by switching off or interrupting, by mechanical or electrical means, the electricity supply from a central flashing pulse generator to the right or left flashing lamp group not selected by the direction indicator switch when the direction indicator switch is switched on. If the direction indicator switch is switched off again while the hazard warning switch remains closed, all the flashing lamps are connected again to the pulse generator.
Because of the electricity supply interruption used, however, the known equipment does not permit the hazard warning function of the equipment to be switched on by subsequent operation of the hazard warning switch when the driving switch and the direction indicator switch are switched on. Because of this, the hazard warning function can be suppressed in certain situations without the knowledge and against the wish of the vehicle driver, even though the driver has correctly switched on the hazard warning switch. This will occur, for example, where in the event of a breakdown, direction indicator signals are first switched on when driving to the side of the road and the hazard warning switch is subsequently switched on to indicate a breakdown while the driving switch or ignition switch is still switched on and because of the small steering wheel deflection, no automatic reset of the direction indicator switch occurs. Similarly, in the known device, the hazard warning signal is suppressed as soon as the driving switch is closed if the direction indicator switch and the hazard warning switch are both closed (because the direction indicator signal then has absolute priority) without any deliberate operation of the direction indicator switch.
Also known is a direction indicator/hazard warning switch arrangement from German Published Unexamined Patent Application No. 1,780,198, which combines both switches in one structural unit and connects them together such that when the direction indicator blinking lamp is switched on and the hazard warning lamp is added, the direction indicator switch returns automatically into the off position, and in the case of the hazard warning lamp being switched on and the direction indicator blinking lamp being added, the hazard warning switch returns automatically into the off position. With this equipment also, therefore, it is possible to switch on the hazard warning signal subsequently (with the direction indicator signal already switched on) by simply operating the hazard warning switch. Because of the mechanical switch reset, however, there is no automatic resumption of a function, such as the hazard warning, for example, after a signal has been given to indicate that a vehicle in trouble is changing direction.
An object of the present invention is to provide a direction indicator and hazard warning device in which a direction indicator signal can be superimposed on the hazard warning signal or a hazard warning signal can be superimposed on the direction indicator signal, for the period while the particular added signal is switched on, by the sole action of arbitrarily switching on the direction indicator switch or the hazard warning switch, respectively.
This and other objects are achieved by providing a direction indicator and hazard warning device for motor vehicles with driving switch means for indicating operation of the motor vehicle. The device includes lamp group means for displaying a direction signal and a hazard warning signal. The device also includes direction indicator switch means mechanically actuable for causing the lamp group means to display a direction signal, while hazard warning switch means are mechanically actuable independently from the direction indicator switch means for causing the lamp group means to display the hazard warning signal. Memory circuit means store and output logic signals, while logic circuit means are connected to the direction indicator switch means and the hazard warning signal means for supplying logic signals in response to open and closed positions of the direction indicator switch means and the hazard warning switch means. The logic circuit means includes connecting elements between each of the direction indicator switch means and the hazard warning switch means and inputs of the memory circuit means. The logic circuit means also includes logic components connected to an output of the memory circuit means. Pulse generator means are connected to the lamp group means for generating the direction signal and the hazard signal in response to actuation of the direction indicator switch means and the hazard warning switch means, respectively.
The connecting elements and the memory circuit means form time sequence control circuit means for controlling the switching element via the logic components and: if the driving switch means is closed, connecting the pulse generator means to the lamp group means, to correspondingly indicate the hazard warning signal or the direction signal in response to whichever of the direction indicator switch means or hazard warning switch means was last actuated, irrespective of the switch position of whichever of the switch means was not last actuated; and if both the direction indicator switch means and the hazard warning switch means have been actuated, and subsequently one of the switch means has been deactuated, connecting the lamp group means to the pulse generator means to indicate either direction signals or hazard warning signals corresponding to whichever switch means remains actuated. The device also includes suppression circuit means connected to the driving switch means for suppressing a control of the memory circuit means resulting from the driving switch means being closed when both the direction indicator switch means and the hazard warning switch means are closed.
This device has the advantage that no absolute priority is provided for a particular flashing signal so that the user of a vehicle can be sure that the signal function which he last switched on manually is actually generated and executed. Provision is made in an advantageous and safe manner, however, to give the hazard warning signal priority whenever the driving switch or ignition switch of the vehicle is opened and subsequently closed again. Using the device according to the invention, the hazard warning signal can only be switched off by switching off the hazard warning switch and can only be suppressed by adding the direction indicator switch with the driving switch closed.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.